Development of Mathematical Models for the Estimation of Dendrometric Variables Based on Unmanned Aerial Vehicle Optical Data: A Romanian Case Study
Research highlights: In this study, the possibility of developing predictive models for both individual trees and forest stands, based on information derived from digital surface models (DSMs), was evaluated. Background and objectives: Unmanned aerial systems (UASs) make it possible to obtain digita...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2021-02-01
|
| Series: | Forests |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1999-4907/12/2/200 |
| _version_ | 1797412373870411776 |
|---|---|
| author | Gheorghe Marian Tudoran Alexandru Claudiu Dobre Avram Cicșa Ionuț Silviu Pascu |
| author_facet | Gheorghe Marian Tudoran Alexandru Claudiu Dobre Avram Cicșa Ionuț Silviu Pascu |
| author_sort | Gheorghe Marian Tudoran |
| collection | DOAJ |
| description | Research highlights: In this study, the possibility of developing predictive models for both individual trees and forest stands, based on information derived from digital surface models (DSMs), was evaluated. Background and objectives: Unmanned aerial systems (UASs) make it possible to obtain digital images with increased spectral and spatial resolution at a lower cost. Based on the variables extracted by means of the digital representation of surfaces, we aimed at generating mathematical models that would allow the prediction of the main biometric features of both individual trees and forest stands. Materials and methods: Forest stands are characterized by various structures. As such, measurements may address upper-level trees, but most often are oriented towards those belonging to the mean tree category, randomly selected from those identifiable from digital models. In the case of grouped trees, it is the best practice to measure the projected area of the entire canopy. Tree and stand volumes can be determined using models based on features measured in UAS-derived digital models. For the current study, 170-year-old mixed sessile oak stands were examined. Results: Mathematical models were developed based on variables (i.e., crown diameter and tree height) extracted from digital models. In this way, we obtained results characterized by root mean square error (RMSE) values of 18.37% for crown diameter, 10.95% for tree height, and 8.70% for volume. The simplified process allowed for the estimates of the stand volume using crown diameter or diameter at breast height, producing results with RMSE values of 9%. Conclusions: The accuracy of the evaluation of the main biometric features depends on the structural complexity of the studied plots, and on the quality of the DSM. In turn, this leads to the necessity to parametrize the used models in such a manner that can explain the variation induced by the stand structure. |
| first_indexed | 2024-03-09T05:01:08Z |
| format | Article |
| id | doaj.art-7013d8aae05449f1a149b68364fd4b43 |
| institution | Directory Open Access Journal |
| issn | 1999-4907 |
| language | English |
| last_indexed | 2024-03-09T05:01:08Z |
| publishDate | 2021-02-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Forests |
| spelling | doaj.art-7013d8aae05449f1a149b68364fd4b432023-12-03T12:59:46ZengMDPI AGForests1999-49072021-02-0112220010.3390/f12020200Development of Mathematical Models for the Estimation of Dendrometric Variables Based on Unmanned Aerial Vehicle Optical Data: A Romanian Case StudyGheorghe Marian Tudoran0Alexandru Claudiu Dobre1Avram Cicșa2Ionuț Silviu Pascu3Forest Management Planning and Terrestrial Measurements, Department of Forest Engineering, Faculty of Silviculture and Forest Engineering, “Transilvania” University, 1 Ludwig van Beethoven Str., 500123 Braşov, RomaniaForest Management Planning and Terrestrial Measurements, Department of Forest Engineering, Faculty of Silviculture and Forest Engineering, “Transilvania” University, 1 Ludwig van Beethoven Str., 500123 Braşov, RomaniaForest Management Planning and Terrestrial Measurements, Department of Forest Engineering, Faculty of Silviculture and Forest Engineering, “Transilvania” University, 1 Ludwig van Beethoven Str., 500123 Braşov, Romania“Marin Drăcea” Romanian National Institute for Research and Development in Forestry Department of Forest Monitoring, 128 Eroilor Blvd., 077190 Voluntari, RomaniaResearch highlights: In this study, the possibility of developing predictive models for both individual trees and forest stands, based on information derived from digital surface models (DSMs), was evaluated. Background and objectives: Unmanned aerial systems (UASs) make it possible to obtain digital images with increased spectral and spatial resolution at a lower cost. Based on the variables extracted by means of the digital representation of surfaces, we aimed at generating mathematical models that would allow the prediction of the main biometric features of both individual trees and forest stands. Materials and methods: Forest stands are characterized by various structures. As such, measurements may address upper-level trees, but most often are oriented towards those belonging to the mean tree category, randomly selected from those identifiable from digital models. In the case of grouped trees, it is the best practice to measure the projected area of the entire canopy. Tree and stand volumes can be determined using models based on features measured in UAS-derived digital models. For the current study, 170-year-old mixed sessile oak stands were examined. Results: Mathematical models were developed based on variables (i.e., crown diameter and tree height) extracted from digital models. In this way, we obtained results characterized by root mean square error (RMSE) values of 18.37% for crown diameter, 10.95% for tree height, and 8.70% for volume. The simplified process allowed for the estimates of the stand volume using crown diameter or diameter at breast height, producing results with RMSE values of 9%. Conclusions: The accuracy of the evaluation of the main biometric features depends on the structural complexity of the studied plots, and on the quality of the DSM. In turn, this leads to the necessity to parametrize the used models in such a manner that can explain the variation induced by the stand structure.https://www.mdpi.com/1999-4907/12/2/200sessile oaktree diametertree heighttree volumecrown diameterstand structure |
| spellingShingle | Gheorghe Marian Tudoran Alexandru Claudiu Dobre Avram Cicșa Ionuț Silviu Pascu Development of Mathematical Models for the Estimation of Dendrometric Variables Based on Unmanned Aerial Vehicle Optical Data: A Romanian Case Study Forests sessile oak tree diameter tree height tree volume crown diameter stand structure |
| title | Development of Mathematical Models for the Estimation of Dendrometric Variables Based on Unmanned Aerial Vehicle Optical Data: A Romanian Case Study |
| title_full | Development of Mathematical Models for the Estimation of Dendrometric Variables Based on Unmanned Aerial Vehicle Optical Data: A Romanian Case Study |
| title_fullStr | Development of Mathematical Models for the Estimation of Dendrometric Variables Based on Unmanned Aerial Vehicle Optical Data: A Romanian Case Study |
| title_full_unstemmed | Development of Mathematical Models for the Estimation of Dendrometric Variables Based on Unmanned Aerial Vehicle Optical Data: A Romanian Case Study |
| title_short | Development of Mathematical Models for the Estimation of Dendrometric Variables Based on Unmanned Aerial Vehicle Optical Data: A Romanian Case Study |
| title_sort | development of mathematical models for the estimation of dendrometric variables based on unmanned aerial vehicle optical data a romanian case study |
| topic | sessile oak tree diameter tree height tree volume crown diameter stand structure |
| url | https://www.mdpi.com/1999-4907/12/2/200 |
| work_keys_str_mv | AT gheorghemariantudoran developmentofmathematicalmodelsfortheestimationofdendrometricvariablesbasedonunmannedaerialvehicleopticaldataaromaniancasestudy AT alexandruclaudiudobre developmentofmathematicalmodelsfortheestimationofdendrometricvariablesbasedonunmannedaerialvehicleopticaldataaromaniancasestudy AT avramcicsa developmentofmathematicalmodelsfortheestimationofdendrometricvariablesbasedonunmannedaerialvehicleopticaldataaromaniancasestudy AT ionutsilviupascu developmentofmathematicalmodelsfortheestimationofdendrometricvariablesbasedonunmannedaerialvehicleopticaldataaromaniancasestudy |